Electric winch control system for alternating currents



June 28, 1949.r K. MAHNKE ELECTRIC WINCH CONTROL SYSTEM FOR ALTERNATING CURRENTS Filed Feb. 28, 1948 INVENTOR N' A/Ur Mah nA/e.

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Patented June 28,n 1949 ELECTRICWINCH CONTROL SYSTEM FOR ALTERNATING CURRENTS Kurt Mahnke, Alden, N. Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 28, 1948, Serial No. 12,097

'l Claims. l

My invention relates to electric control systems for Winches such as warping or mooring Winches, towing Winches, cable laying reels, or the like machinery.

It is an object of the invention to devise control equipment that is capable of an automatic performance in response to the pull, tension, or payed-out length of the winch rope and permits using an alternating-current motor for controlling the winch drive to maintain the pull, tension, or length of the cable within the desired limits.

Another object of th-e invention is to devise an alternating-current Winch control system which permits operating the winch motor at selective speeds in heave-in and pay-out directions in such a manner that the maximum torque of the motor is smaller when paying out than when heaving in so that protection is provided against the occurrence of excessive rope tension due to winch friction rope, when paying out, without necessitating additional protective control switches.

These and other objects, as well as the means provided by the invention for achieving the objects, will be apparent from the following description of the embodiment exemplified in the drawing by a circuit diagram of a marine winch shown in Fig. l and an explanatory diagram of speedtorque characteristics shown in Fig. 2.

in Figure 1, the winch drum I is connected through a gear box 2 with an alternating-current winch motor M and is equipped with a normallyset friction brake 3 which has an electromagnetic release magnet 4. The brake magnet is controlled by contacts 5, 6 and 1 of a brake relay BR which has a self-holding contact 8 and a relay coil 9. Brake coil, motor, brake relay, and all other relays described hereinafter are energiaed from alternating-current leads LI, L2, L3 through a main switch I which is closed when the system is in operative condition.

The motor M is of the multi-speed squirrelcage type. That is, it is equipped with several stator windings or winding sections for producing motor fields of respectively different pole numbers. In the illustrated example, the motor is assumed to have two such stator windings. One winding is subdivided to produce either a eld with 24 poles for operation at 300 R. P. M. or a field with 12 poles for operation at 600 R, P. M., depending upon how the two parts of the winding are connected. The motor terminals for operation at 300 R. P. M. are denoted by II. Those for operation at 600 R. P. M. are

denoted by I2. Terminals II are to be short circuited when terminals I2 are energized. The other eld Winding is connected to the terminal group I3 and designed for producing a motor field with four poles for operation at 1800 R. P. M.

The energizaticn of the motor terminal groups from the leads LI, L2, L3 is controlled by two reversing relays P and I-I, and also by contactors denoted by IM, 2M, 20M, 3M and 4M. Relay H (heave-in relay) has three main contacts I4, I5, I6 controlled by a coil I1 which actuates also two interlock contacts I3, I5. Relay P (pay-out relay) has three main contacts 2I, 22, 23 and two interlock contacts 2li, 25 under control by a coil 26. The polarity or phase sequence of connection of relay H is different from that of relay P, so that, when relay H is energized, the phase sequence of the voltage applied to the motor is such as to produce motor torque in the heavein direction while when relay P is energized, the phase sequence is reversed to produce motor torque in the pay-out direction. Interposed between the supply leads LI, L2, L3 and the contacts 2l, 22, 23 of th-e pay-out relay P are three resistors 21, 23, 29. It will be recognized that these resistors are series connected to the motor only when the motor is to operate in the pay-out direction. These resistors then have the eect of limiting the maximum torque and maximum current of the motor to values lower than the respective Values possible during heave-in operaion.

The contactor IM has main contacts 3l, 32, 33 connected to the terminal group II for lowest motor speed and controlled by a coil 34 which also actuates an interlock contact 35. Three resistors 36, 31, 3B are series connected between contacts 3|, 32, 33 and the main contacts of relays P and H. These resistors are effective in the motor circuit during both heave-in and pay-out operations unless they are short circuited by the contactor 3M. The contactor 2M has main contacts 4I, 42, 43 disposed between the terminal group I2 for medium speed and the resistors 36, 31, 38. Contacter 2M has also two interlock contacts 44, 45 and a coil 46. Relay 29M has two contacts 41, 48 for short circuiting the terminals II under control by a coil 49. The contacts of relay 3M for short circuiting resistors 36, 31, 38

lare denoted by 5I, 52, 53. The appertaining relay coil is denoted by 54. Relay 4M has main contacts 55, 56, 51 and an interlock contact 58 under control by a coil 59. Contacts 55, 56, 51 are connected between the terminal group I3 and the operation off the Selector switch 60 has an o position denoted by O and several operating positions denoted by heave-in I, 2, 3, 4 and pay-out 2, 4f.,

In addition, switch 60 has an.. automatic position A to which the switch must be' adjusted in order to put the automatic switch 80 in operation. Switch 60 has also a drift posit'oniDinawhichfthe motor M remains deenergized! While-the brake 3:'

is lifted in order to make the winch or ropefreely-y revolvable. A spring mechanism, schematically shown at 6|, serves to bias the switch 80 from position D and pay-out positions I, 2 and ltitoward position A. That is, the switch 60 will remain inthe positions Band atpay-out points; I, 2 and. 4f only as long as the'switchis heldin these posi-- tionsby theroperator, but. Will automatically turn to position A. when t-he operator' releases the. switch.

Switch 80y hasseveral pay-out positions and several heaveein: positions: It isy connectedthrough al suitable transmission, here schematically represented by` a dot and dash line 8|-, to an: output shaft82 of'` the-gear box 2. The purpose of this transmission between switch 8! and motor M is to control the switch in dependence upon the departure? of the w-inch.- or rope condi'- tion from a given operating range. rThe gear 2- may consist of az tensiometric device' Well known for. the automatic. control? of towing Winches; Suchv a tensiometric device consists essentially of a diiferential or planetary gearing whose two input shafts are connected to the; motor and the winch drum respectively While the diierential member is attached tothe control. switch and is biased by a: spring to-deect from its normal position.- of rest only when` the difference between motor torque and: drum` torque exceeds given limits, the direction of. deflection being in. accordance with the direction of the differential. torque value. Since suchtensiometric. devices are well known aswill. be seen,.for instance, from. United States. Patents 2,393,048' and! 2,414,473,v andv since the particular design ofthe condition-responsive device isnot an essential' feature of the invention proper, the details ofY this device are not illus,- trated in the drawing. 1t. should be. understood that', if desired', the shaft 82'. may be connected with the motor shaft by a limit device so that shaft 82 is turnedv only Whenthe length of rope paid out by the winch d'rum exceeds adjusted limit values. Such limit devices are also well known in the art for" winch control. purposes.

The two switches 6U' and' '8U' are represented in developed form and by' the schematic illustration customary for cam controlled master switches. If desired, however,A drum type con'- trollers or contact' devices of any' other suitable type may bei used instead.

It is assumed in' the following description of system that switch |f|Il is closed and thatr the' leadsfLI, L2, L3@ are properly energized.

Manual' operation Point |'--Payout':. When the manual switch 6U' i's moved from the oif position through positions A and Dto position I", pay-out, coil 26 of relay Pl is energized in theei'rcuit L|9|6| 26-I9-9'2f'-L2. Relay 'Pg picks up and' energizes coil 9 of brake relay BR in the circuit L|-9|- 24 9-92-L2. Brake 3 is released and contacts 2|, 22, 23 `of relay P close. Contact IM picks up because its coil 34 is energized in the circuit L|-l|60344492L2 so that contacts 3|, 32, 33 close. Terminal group of motor M is now energized through contacts3t, 32; 33', resistors 36, 31, 38, contacts 22|-, 22, 23. and resistors 21, 28, 29. Motor M runs at 300 R. P. M. (synchronous speed in the heave-in direction. A typical speed torque characteristic corresponding to thisperformance isshown at PI in Fig. 2.

Point Z-Pay-out: When switch 60 is moved to position 2 pay-out,l contactor M drops out and coils 48' and. 49101 contactors M2 and M20 are energized soithat. these contactors pick up. Now, the terminal` group is shorted at contacts 41, 48" andA the terminal'group I2 is energized through contacts 4|, 42, 43 and resistors 36, 31, 38 and 21, 28, 29. The motor now runs in the pay-out directionat 600R..P. M. with aspeedtorque characteristic typiedbycurve P2 in\Fig. 2.

Point. 4--Pay-out: Contactors M2l and M20 drop out and coil 59 of contacter 4M' is energized sothat contactor 4M applies voltage izo-terminal group I 3 through. contacts 55; 58, 5-1. The resistors 36 31', 38- are nolonger effective, While resistors 21,4 28., 2.9- remaixr series-connected in the motor circuit. The motor now` runs at 1-800 R. P. M'. with a speed torque! characteristic as exempliiied. by thev curve P4` in Fig. 2.

Point I-Heave-in: Coil I1 of relay H is energized in all. heave-in positions so that contacts I4, I5, I'B are closed. Contact I-l` energizes the brake relay coil `9 so that the brake is released. When. switch. 60: is' in position I, heave-in, the c0il 34 of contactor IM is' also' energized so that contacts 35|,v 32, 33 arel closed; Terminal group II is energized.v through contacts 3|', 32, 33, resistors-36,31', 38 and conta-cts |-4, I5, I6. Motor M runs. inf thel heave-in' direction at 3'00 R. P. M. with resistors- 36; 31',l 38 effective to limit. motor current and torque though in a lesser degree than during: pay-out performance because resistors21, 281,. 29 are not effective in. any heave-in' posi-tion; An example-f of" a corresponding motor. characteristic is. represented byA curve HI in Fig. 2.

Point 2--Hea-ve-in.: Contactor. IM drops out and contactors 2M. andi 2.6M pick'. up'.v Motor M is' energizedz at terminar group I 2. through contacts: 4|, 42., 43, resistors. 33,. 3.1i, 38 and contacts I4',. t5 and |62.. Terminar groupl III-f issnorted at contacts 412,481. The' speed torque characteristic of motor Munder these conditions is representedbyfcurve H2iin' Fig. 2..

Point 3-Heavein: Contactors- 2M and 20M remain picked' up, and contactor 3M picks up in` addition. Hence; themotorv energizing circuit remainsithefsame asQfor point 2', heave-in, except that the contacts 5|?, 52, 531I of'c'ontactor 3M short the resistors 36, 311?, 38" andpermit the motor to-dra'w more current. Hence the-motor may develop a higher' heave-inl torque as exemplified by the characteristic H3 infFlg. 2".

Point14`-Heave--in: Contacto'rs 2ND, 20M a-nd 3M drop out. Contactor 4M picks up'4 and energizes terminal"v group |31' through contacts 55, 56, 51 and; contacts I4, I5?, |6=`. Motor M runs in heavein direction at 180'0v R. P.' Ml with a speed torque characteristic as exemplh'e'd by curve H4 in Fig. 2. The motor iieldl winding nowenergized has a considerably higher resistance thanthe one previously effectiveso that current and torque are reduced accordingly.

Automatic operation During towing or warping, the winch rope is to be automatically held within given limits of rope tension (or Within given limits of paid-out rope length). This automatic performance is effected by the switch 8|] when the manual switch 60 is placed in the automatic position A. As long as the cable pull remains within the desired limits, switch 80 is in the off position in which the brake 3 is set and the whole system deenergized. Consequently, under fairly stationary conditions, no current is consumed by the system and the necessary drum holding force is provided only by the friction brake. When the rope slackens so that its pull on the winch drum drops below a minimum value, the shaft 82 of the tensiometer gearing 2 turns the switch 80 in the heave-in direction. Switch 80 then passes through positions I and 2 and may reach the position 3. When passing through position I, heave-in, the switch 80 prepares two circuits: one for coil I1 of relay H, and another one for coils 45, 49 of contactors 2M and 20M. These circuits extend through the self-holding contact 8 of the brake relay BR; but since contact 8 is then open, neither relay H nor contactors 2M and 20M pick up. As soon as switch 80 reaches position 3, heave-in, the two coil circuits are closed at contact 8 as follows: The circuit for coil I1 of relay H extends through elements LI-Q I--GD-S-SM- 80-25--I1-92-L2; and the circuit for coils 45 and 49 extends from lead `9| through switch. 60 and through contacts '58, 35 to coils 45, 49 and thence through lead 92 to line L2. Relay H and contactors 2M and 20M pick up. Relay H energizes coil 9 of brake relay BR in the circuit LI-SI--24-9-82-L2 so that the brake 3 is released while the motor is now energized to run in the heave-in direction substantially in accordance with the characteristic H2 in Fig. 2. Thereafter, the brake relay BR is held in together with relay H because contact 8 is now closed. Relays BR and H are released only when the increasing pull of the rope being heaved-in causes the switch 80 to return to the off position.

When the towing or warping load becomes too great so that the rope tension exceeds the desired maximum value, shaft 8| turns the switch 80 through pay-out positions I and 2 to position 3. As switch 80 passes through position I, a circuit is prepared for coil 34 of contacter IM and another circuit for coil 26 of relay P. These circuits are completed only when switch 80 reaches the position 2, pay-out. Then the brake is released and contactor IM connects terminals Il to the line through contacts 3I, 32, 33, resistors 36, 31, 38, contacts 2|, 22, 23 and resistors 21, 28, 29. If the amount of rope now being paid out is insuilicient to relieve the excessive rope pull, the switch 80 moves farther to position 3. As a result, contactor IM drops out and contactors 2M and 20M come in. Now the motor terminals I2 are energized for 600 R. P. M. operation with resistors 36, 31, 38 and resistors 21, 28; 29 effective to limit the current and torque of motor M. When due to the paying out of rope, the rope pull and tension decline, switch 80 turns back to the off position but, as during the automatic heave-in performance, the motor becomes deenergized and the brake is set only when switch 80 reaches the off position.

It will be recognized from the foregoing description that when operating at minimum speed in the heave-in direction, the series resistors other in which the resistors are ineffective.

36, 31, 38 vare connected in the motor circuit and that at medium speed two operating points for heave-in operation are provided, one in which the same series resistors are effective and an- If desired, the series resistors may also be made effective when operating at high speed, but no resistance need be inserted if, as assumed in the illustrated embodiment, the high speed winding of the motor has sufficient inherent resistance to prevent high current peaks. When paying out at low and medium speed, the same resistors 36, 31, 38 are effective but, in addition, the resistors 21, 28, 29 are also series connected in the motor circuit and remain in that circuit regardless of the selected motor speed. This has the following result. When heaving-in, the motor overcomes rope pull plus winch friction. When paying out, the rope pull overcomes motor torque plus winch friction. Hence, if the maximum torque of the motor were the same for paying out and heaving-in, the pull and tension of the rope would `be much higher when paying out than when heaving in so that the rope strength is either not suiciently utilized during heave-in operation or the rope is exposed to danger of overstress when paying out. However, by virtue of the increased resistance of the motor circuit during pay-out performance and the limitation thus imposed on the motor torque, the rope can be stressed the permissible maximum value when heaving-in without exceeding this value during pay-out performance.

Another advantage during pay-out performance is the fact that it limits the motor current if the rope is pulled oif the drum at high speed and the motor, while connected to the low speed winding, is being overhauled at high speed.

While some possibilities of modifying the system have .been mentioned in the foregoing, it will be understood by those skilled in the art after a study of this disclosure, that other changes especially as regards the design, arrangement, and circuit connections of the system comlponents can be made without obviating the objects and advantages of the invention and without departing from the essential features of the invention as set forth in the claims annexed hereto.

I claim as my invention:

1. An electric winch control system, comprising a multi-speed alternating-current winch motor having a plurality of terminal groups for operating at different speeds respectively, alterhating-current supply lead for energizing said motor, a plurality of contactors connected to said terminal groups respectively, two reversing relays, each being connected between said leads and said contactors, said relays having different respective polarities of connection for controlling said motor to run in heave-in and pay-out directions respectively, a multi-position selector switch connected to said relays and said contactors for selectively controlling them to connect one of said terminal groups at a time through one of said respective contactors and one of said respective relays to said leads so that running direction and speed of said motor depend upon the selected position of said switch, and resistance means series-connected between said terminal groups and said leads under control by one of said relays so as to be active only when said motor is connected for paying out performance.

Y 2. An electric winch control system, comprising a multi-speed alternating-current winch motor having.. a'. plurality of terminali groupsfon operating' aty diierent speeds. respectively alter hating-current sulpply' leads: for energizingi said!` motor, a `plurality of. contactors-each' having' a'l controlcoil and; contacts: controlledby. saidfcoil: and: connected to'one off said: respective termi.- nal groups, aheave-in relayrand a'pay-out relay. having. respective control coils and: having'. respective Contact. means dispose' between said?. leads andsaid contacter. contacts, said tWo;re:- lay.Y contact means having diierent respective; polarities of connection for. controlling .said motor to runin heave-in andipayout` directionszrespec.- tively, resistance means. series-connected with". said contact means of' said'lpay-out relayqbetween; said leads and said capacitor contacts, and a: multi-position selector. switch connected'to. said: coils-for selectively controlling said relays andl said'contactors to connect atta time oneof'said. respectiveuterminal:groupsftot said leads through. the contacts of one of said' respectivev contactorsv and the contactv meansof one offsaid'respective relays.

3; Anelectric winch control system, comprising a. multi-speed alternating-.current winch motor having a plurality of terminalgroups for operating'at' different` speeds respectively, alter'-` natin'g-current supply leads for energizing said. motor, control means. disposedv between said terminalgroups and-.saiddeads and having a multim position selector switch forv connectingsaidileads.- to one of said respective-terminal groups at ay time, resistance means .serieswonnected between, one ofA saidterminal. groups and said leads, and

circuitrneans connecting said; resistance means.V

with said selector suitable for:` controlling said' resistance. means to be active. in one position and inactivein anotherposition of: said switch,-v said leadsbeing. connected` tosaid one terminal g-roup in both latter: positions of saidiswitch.

4. An electric winch control system, comprising a multisspeed.alternating-current'winch mo-v tor having. a plurality of terminal groups for operating at different speedsrespectively, alter-A nating-current supply leadsfor` energizing saidI motor, resistance `means series-disposed.; between said `motor and said leads, aplurality of' contactors eachhavingl contacts connected'betw'een said leads and one of said respective terminal.' groups, another contacter.` having contacts for controlling` said resistance: means, and' a Y multiposition selector switch connectedto saidplu-l rality oi contactors for-controlling. themto selec-y tively connect said-respeetive'terminal groups to saidzleads, said switchhaving two adjacent posi-u tions and contact means fori causing one of. said pluralityof contactors to connect the samek ter--v minal group to said leads in both adjacent posi-- tions and having othery contactmeans-connected. to said other contactor for controlling.y said resistance means tobe; active in only-one-pf said: adjacent positions.

5. An electric winch control system, compris-` ing a multi-speed alternating-current. winch mo-A tor having aplurality of terminal groups forl operating at different speeds respectively, alter-- netting-current supply leads for energizing saidA motor, reversing contact: means disposed'b etween: said leads and said vmotor for controlling the; running direction of. said. motor", twovv selector; switches each with a multi-position switchmerm` ber having an ofi position andtwo groups of; active positions on both sides." of saidLoiT posi..-y tion, each of-saicl membershavingicontactimeans connected to said reversing means-tddetermineiy groups and' connected-to saidtwo-membersso asv to connect said'respective terminal group,one.atvv a'tizne, to said'leads `when either member/is inre-` spective active positions, one of said switchfmern-A bers being manually operable and having another;

position and havingfadditional contact means:

connected to said other switch to render said! other switch effective only when said manually operablemember is placedin saidother position, and actuating meansiconnected-.with saidfmotor.

- j andhaving a movablemember controlled. in de-A pendence upon a winch operating condition and: connected to .said other switch member for automatically operating the latter inorder to maintain said-condition with givenilimit'values.

6. An electric winch control system, comprising amulti-speed alternating-current winch motor having av plurality ofl terminal groups for operating at different speeds. respectively, alter-l nating-current supply leads for energizing said motor, reversing contact means. disposed be-v tween said leads and saidimotor fory controlling the running direction of said motor, twoselectorv switches each with a multi-position switchimember having an on position andztwoigroups of; active positions on both sides of. saidoi position, each of said members having 'contact meansv connected to said reversing meansfto determine the running direction of saidmotoi-.in accordance with the selected group of contactlme'ans, `a plurality of contactors disposed between said'revers.- ing contact means and said respective?l terminal groups and connected to said;tWo..m-embers so as to connect said respective terminal group, one; at a time, to said leadsfwhen either member is. in respective activel positions, onev of said switch members being manually operableand having another positiona andi having' additional contact means connected to said. other switch to render said other switch eiective'. only' when said;manually operable member is placed. insaid other position, a winch drum lmechanically connectedy to said motor, andia. tensiometricf device interposed between saiddrum andrsaidmotor'and hav-l ing a reversibly movable outputl elementy con.-Y nected to said other switch member forv auto-- matically positioning the latterin; the direotionl required to maintain-the Winch pull within given. limit values.

7. An electric winch control system, compris-l ing a multi-speed alternating-current winch motor having a plurality of terminal. groups for operating at different'. speeds respectively, alter-- hating-current supply leads, a pluralityof contactors disposed between saidileadsand said respective terminal groups, reversing` rel-ay, means disposed between said contactors andrsaidleads. for controlling the running'v direction. of said motor, a selector switch-having an oil?. position and two groups of active positions on both respective sides 'of said offlposition, a'tensiometrici device associated with said motor and: having a' reversibly' movable element connected. to said switch for positioning. said` switch. abrake.l associated'with saidmotor, a brake relay disposed. for controllingsaid brake and having alnormallyopen self-holdingr circuit, saidswitch'having oon-v tact means connected through said: self-holding.v circuit.. to'.5 said contactors 1 and' to` said reversing relayimeanss and disposed':for'control1ingsaidxcon taetors and'relayf mean'sa-when said; self-holding contact is closed, to connect one of said respective terminals at a time to said leads so that said motor runs in a direction determined hy the selected group of contacts, said switch having other contact means connected with said brake relay and disposed to energize said brake relay when said switch is in an active position other than those immediately adjacent to said off position so that'said brake is released and said motor energized only when said switch has passed from the off position through an adjacent position but remains released and energized, due to said self-holding circuit, when thereafter said switch turns back to the adjacent position until it reaches the oi position.

KURT MAHNKE.

REFERENCES CITED The following referenlces are of record in the le of this patent:

UNITED STATES PATENTS 

